ABS plastic compositions containing bio-phenoxy flame retardants

ABSTRACT

Plastic compositions containing acrylonitrile-butadiene-styrene and bis-phenoxy compounds having the formula   WHEREIN Z is bromine, m and m&#39;&#39; are integers having a value of 14, i and i&#39;&#39; are integers having a value of 1 or 2, alkylene is a straight or branched chain alkylene group having from 1 to 6 carbon atoms and A is either cyano, nitro, lower alkoxy, lower alkyl, fluorine, dialkylamino, phenyl, halo-phenyl, benzyl or halo- benzyl.

United States Patent [191 Anderson et a1.

[ May 13,1975

1 1 ABS PLASTIC COMPOSITIONS CONTAINING BIO-PHENOXY FLAME RETARDANTS[75] Inventors: Arnold L. Anderson; Robert J.

Nulph, both of Alma, Mich.

[73] Assignee: Michigan Chemical Corporation, St.

Louis, Mich.

[22] Filed: Feb. 8, 1973 [21] Appl. No.: 330,820

Related U.S. Application Data 1 [63] Continuation-impart of Ser. No.260,240, June 6,

1972, abandoned.

[52] U.S. Cl..., 260/459 R; 260/42; 260/4222; 260/4575 R; 260/4595 G[51] Int. Cl. C08f 45/60 [58] Field of Search 260/459 R, 45.95 G, 613 B,260/332 R, 2.5 A], DIG. 24; 106/15 F? [56] References Cited UNITEDSTATES PATENTS 3,658,634 4/1972 Yanagi et a1 161/403 3,717,609 2/1973Kutner 260/4595 G Primary Examiner-M. .1. Welsh Attorney, Agent, orFirm-Robert M. Phipps; James J. Mullen; Robert S. Frieman ABSTRACTPlastic compositions containing acrylonitrilebutadiene-styrene andbis-phenoxy compounds having the formula 0 --(a1kylene) 0 I Z 17 Claims,No Drawings 1 ABS PLASTIC COMPOSITIONS CONTAINING BIO-PHENOXY FLAMERETARDANTS This application is a continuation-in-part of copendingapplication Ser. No. 260,240, filed June 6, 1972 and now abandoned. Theentire specification of this case, Ser. No. 260,240, is to be consideredas incorporated herein by reference.

The prior art considered in conjunction with the preparation of thisapplication is as follows: US. Pat. Nos. 2,130,990; 2,186,367;2,329,033; 3,666,692; 3,686,320; 3,658,634; German Pat. Nos. 1,139,636;2,054,522; Japanese Pat. No. (72) 14,500 as cited in Volume 77, ChemicalAbstracts, column l53737k (1972); Chemical Abstracts, Volume 13, column448 Chemical Abstracts, Volume 31, column 7,045"; and Journal of theChemical Society, pages 2,972-2,976 (1963). All of these publicationsare to be considered as incorporated herein by reference.

The present invention relates to plastic compositions containingacrylonitrile-butadiene-styrene (herein referred to as ABS). Morespecifically, the present invention covers plastic compositionscontaining ABS and certain bis-phenoxy compounds (hereinafter defined)as flame retardants for said plastic compositions.

ABS plastics and utility thereof are known in the art as exemplified byABS Plastics, C. H. Basdekis, (Reinhold Plastics Applications Series),Reinhold Publishing Corporation, New York, 1964 and Modern PlasticsEncyclopedia 1972-1973, Vol. 49: No. A, October,1972,pages10,14,16,17,l9,142 and 143 and which publications are in totoincorporated herein by reference.

The need for flame retarding ABS plastics has also been recognized inthe art as exemplified by US. Pat. Nos. 3,422,048 and 3,418,263 andModern Plastics Encyclopedia, ibid, pages 142, 143, 202, 203 and 456-458and which publications are in toto incorporated herein by reference.

The resultant disadvantages in the utilization of various prior artmaterials as flame retardants for ABS include, without limitation,factors such as thermal migration, heat instability, light instability,nonbiodegradable, toxicity, discoloration and the large amounts employedin order to be effective. Thus, there is always a demand for a materialwhich will function and/or physical and/or mechanical properties of theresultant ABS plastic composition.

The prior art problem of providing a flame retarded ABS compositionhaving desired chemical, physical and mechanical properties has now beensubstantially solved by the present invention and the abovedescribeddisadvantages substantially overcome.

Accordingly, one of the main objects of the present invention is toprovide ABS plastic compositions which are flame retarded.

Another object of the present invention is to provide a material for ABSplastic compositions which will not substantially adversely effect thechemical and/or physical and/or mechanical properties of saidcompositions.

A further object of the present invention is to provide a flameretardant which is economic and easy to incorporate into ABS plasticswithout being degraded or decomposed as a result of blending orprocessing operations.

It has been fou'ndthat the foregoing objects can be obtained by theincorporation of a new class of bisphenoxy compounds inacrylonitrile-butadiene-styrene to subsequently provide flame retardedcompositions which exhibit outstanding chemical, physical and me- 5chanical properties.

as a flame retardant in ABS and concurrently will not, by incorporationtherein, adversely effect the chemical The bis-phenoxy compounds used inthe present invention compositions have the formula:

0 (alkylene) 0 2 ln Formu1a I above, Z is bromine; m and m are integerseach independently having a value of l-4; i and i are integers eachindependently having a value of l or 2; alkylene is a straight orbranched chain alkylene group having from 1 to 6 carbon atoms (e.g. CH C11 C ll C H C l-l C H and CH CH(CH )Cl-l and A is from the group cyano(CH), nitro (NO lower alkoxy (e.g. OCl-l OC H lower alkyl (e.g, CH C H Cl-l C 11 fluorine, dialkylamino e.g., N(CH3)2, N(C H phenyl (C Hhalophenyl, benzyl (CH C H and halo-benzyl.

ln FOrmula l, i or i is 1 when m or m is 4, respectively.

It is to be understood that all of the compounds falling within theabove Formula I and as heretofore defined are generically describedherein as bis-phenoxy compounds.

Illustrative (but without limitation) of some of the present inventionbis-phenoxy compounds are shown below:

0 (a1kylene)- 0 the exemplary definitions of A, A, i, i, m, m andalkylene are listed in Table l.

Table l Compound No in m'A 1 1' Alkylene 1 Br 2 2 CN l l CH 2 Br 2 2 F 11 c 11,

3 Br 2 2 CN 1 l C l-[ 4 Br 2 2 CN 1 l C H,

5 Br 2 2 NO l 1 C l-h 6 Br 2 2 ocH,, 1 1 c 11,

7 Br 3 3 OCH3 l l C l-L,

8 Br 2 2 c11 1 1 C 11,

9 Br 2 2 l 1 C 11,;

ll Br 2 2 H l l C2H4 13 Br 2 2 CH C H l l C l-l 15 Br 3 3 -c,-,H, :1 1 1c 11 16 Br 3 3 1 1 c u,

19 Br 3 3 C H Br 1 1 c n,

20 Br 3 3 NO, 2 2 c 11 21 Br 2 2 CN 1 l CH(CH -,)CH 22 Br 4 4 NO l 1CH(CH )CH CH 23 Br 3 3 2 2 CH CH(CH )CH CH 24 Br 1 l C,H l 1 CH 25 Br 1l OCJ-l l l C H In general, the bis-phenoxy compounds are prepared byreacting a halogenated phenol with a halogenated alkane at elevatedtemperatures in the presence of a basic material such as alkali metalhydroxides, carbonates, bicarbonates, oxides and hydrides. The preferredalkali metals are potassium and sodium. Where one desires to increase,for example, ease of handling the reaction mass; solvents such asketones (e.g. acetone, methyl ethyl ketone, and methyl iso-butylketone), alcohols (e.g. methanol, ethanol, iso-propyl alcohol, butylalcohol and glycols), or aqueous solvents (e.g. water, a mixture ofwater and alcohol and a mixture of water and ketone) can be employed.The desired end product, i.e. the bis-phenoxy compound, can be recoveredfrom the reaction mass via various methods such as distillation orcrystallization. Where the end product requires recovery viacrystallization, various aromatic solvents such as benzene, toluene,xylene, dichlorobenzene and the like can be used.

Specifically, the bis-phenoxy compounds are prepared according to thefollowing reactions:

2' Z 0H X(lkylene)X Z O (alkylene) 0 r In the above reaction, X ishalogen, preferably chlorine and alkylene is the same as herein defined.Where mass to the boiling point thereof. Preferably the temperatures arefrom about 40 to about 200 C and more preferably from about 50 to aboutC. It is to be understood that the reaction can be conducted undersub-atmospheric (e.g., l/lO-8/l0 atmospheres), atmospheric orsuper-atmospheric (e.g. 1.5-10 atmospheres) pressure. Preferably, thereaction is carried out at atmospheric pressure.

The above-described processes can be carried out with conventional,readily available chemical processing equipment. For example, aconventional glass-lined vessel provided with heat transfer means, areflux condenser and a mechanical stirrer can be advantageously utilizedin practicing any of the preferred embodiments of the inventiondescribed in the examples set forth herein.

The amount of bis-phenoxy compound employed in the present inventioncompositions is any quantity which will effectively render theacrylonitrilebutadiene-styrene containing composition flame retardant.In general, the amount used is from about 1 to 25 percent by weight,based on the total weight of the composition. Preferably, the amountemployed is from about 5 to about 20 percent by weight. It is to beunderstood that any amount can be used as long as it does notsubstantially adversely effect the chemical and/or physical and/ormechanical properties of the end polymer composition. The amountutilized, however, is such amount which achieves the objectivesdescribed herein.

It is to be understood that the term ABS as used herein meansacrylonitrile-butadiene-styrene copolymers which are thermoplasticpolymers produced, for example (but without limitation), by blending astyrene/acrylonitrile copolymer with butadiene-based rubber, or bygrafting butadiene-based rubber (usually polybutadiene) withstyrene/acrylonitrile chains, or by copolymerization of styrene,acrylonitrile and butadiene monomers.

Thus the acrylonitrile-butadiene-styrene used in the present inventioncompositions is any acrylonitrilebutadiene-styrene herein defined andwhich one so desires to flame retard. It is to be understood that theacrylonitrile-butadiene-styrene used can be a virgin material, i.e.substantially free of additives such as stabiliz- ZHX ers, plasticizers,dyes, pigments, fillers, and the like, or theacrylonitrile-butadiene-styrene can have additives (such as thosementioned and described herein) already contained therein or addedconcurrently with or after the addition of the bis-phenoxy compounds.

Another facet of the present invention relates to the use of certaainmetal-compounds with the bis-phenoxy compounds to promote a cooperativeeffect therebetween and thus enhance the flame retardancy of theresultant plastic composition as compared to the flame retardancy ofeither one component used separately. These enhancing agents are fromthe group antimony, arsenic, bismuth, tin and zinc-containing compounds.Without limitation, examples of said enhancing agents include Sb O SbClSbBr Sbl SbOCl, As O As O ZnBO,BaB O -H O, 2-ZnO'3B O -3.5- H 0 andstannous oxide hydrate. The preferred enhancing agent is antimonytrixode.

The amount of enhancing agent employed in the present inventioncompositions is any amount which when used with said bis-phenoxycompounds will promote a cooperative effect therebetween. ln ggeneral,the amount employed is from about 1 to about 15 percent, preferably fromabout 2 to about percent, by weight, based on the total weight ofplastic composition. Higher amounts can be used as long as the desiredend result is achieved.

It is also within the scope of the present invention to employ othermaterials in the present invention compositions where one so desires toachieve a particular end result. Such materials include, withoutlimitation, adhesion promotors; antioxidants; antistatic agents;antimicrobials; colorants; flame retardants such as those listed onpages 456-458, Modern Plastics Encyclopedia, ibid, (in addition to thenew class of flame retardants described herein); heat stabilizers; lightstabilizers; pigments; plasticizers; preservatives; ultravioletstabilizers and fillers.

In this latter category, i.e. fillers, there can be mentioned withoutlimitation, materials such as glass; carbon; cellulosic fillers (woodflour, cork and shell flour); calcium carbonate (chalk, limestone, andprecipitated calcium carbonate); metal flakes; metallic oxides(aluminum, beryllium oxide and magnesia); metallic powders (aluminum,bronze, lead, stainless steel and zinc); polymers (comminuted polymersand elastomer-plastic blends); silica products (diatomaceous earth,novaculite, quartz, sand, tripoli, fumed colloidal silica, silicaaerogel, wet process silica); silicates (asbestos, kaolimite, mica,nepheline syenite, talc, wollastonite, aluminum silicate and calciumsilicate); and inorganic compounds such as barium ferrite, bariumsulfate, molybdenum disulfide and silicon carbide.

The above mentioned materials, including fillers, are more fullydescribed in Modern Plastics Encyclopedia, ibid, and which publicationis incorporated herein (in toto) by reference.

The amount of the above described materials employed in the presentinvention compositions can be any quantity which will not substantiallyadversely effect the desired results derived from the present inventioncompositions. Thus, the amount used can be zero percent, based on thetotal weight of the composition, up to that percent at which thecomposition can still be classified as a plastic. In general, suchamount will be from about 0 to about 75 percent and specifically fromabout 1 to about 50 percent.

The bis-phenoxy compounds can be incorporated in to theacrylonitrile-butadiene-styrene at any processing stage in order toprepare the present invention compositions. In general, this isundertaken prior to fabrication either by physical blending or duringthe process of forming acrylontrile-butadiene-styrene per se. Where oneso desires, the bis-phenoxy compounds may be micronized into finelydivided particles prior to incorporation into theacrylonitrile-butadiene-styrene.

EXAMPLE I An ABS plastic material, (Marbon TP-2098, a product of MarbonDivision, Borg-Warner Corporation, Washington, West Virginia andcontaining antioxidants, lubricants, releasing agents and titaniumdioxide pigment, and prepared according to the processes described andclaimed in US. Pat. No. 3,238,275 issued on Mar. 1, 1966) is utilized asthe base resin in order to prepare 26 formulations (plasticcompositions). With the exception of formulation No. 1, the particularbis-phenoxy compound (and the antimony trixode enhancing agent whereindicated) is incorporated into the plastic by adding both to aBrabender mixer (Plastic- Corder, Torque Rheometer, Model PLV-150, C. W.Brabender Instruments Inc., South Hackensack, N.J.). The mixer isequipped with a pair of roller type blades positioned within a headprovided with heat transfer means.

The resultant mixture is heated to about 245 C.; at this temperature, itis in a molten state. The percentages by weight of each componentutilized in the respective formulations are listed in Table II. Eachformulation is discharged from the mixer and upon cooling solidifies andis ground into chips. The chips are subjected to compression molding ina Wabash press by placing said chips between two platens, the bottom ofwhich contains four equal size depressions three inches by 5 inches byA: inch deep. The top platen is then placed over the bottom platen andheat transfer means supplied thereto in order to melt said chips andthus provide solid samples (after cooling) for testing.

Portions of the solid samples of each respective formulation (Nos. l-26)prepared according to the above described procedure are then subjectedto two different standard flammability tests, i.e. UL 94 and ASTMD-2863-70. The UL 94 is, in general, the application of a burner to atest specimen (strip) for a certain period of time and observation ofcombustion, burning, and extinguishment. This procedure is fully setforth in Underwriters Laboratories bulletin entitled UL 94, Standard forSafety, First Edition, September, 1972 and which is incorporated hereinby reference. ASTM No. D-2863- is a flammability test which correlatesthe flammability of a plastic specimen to the available oxygen in itsimmediate environment; this correlation is stated as an Oxygen Index,0.1., level predicated upon the percent oxygen in the gaseous mediumwhich is required to just provide a steady state of continuous burningof the plastic specimen. This ASTM method is fully described in 1971Annual Book of ASTM Standards Part 27, published by the American SocietyFor Testing and Materials, 1916 Race Street, Philadelphia, Pa.; thispublication is to be considered as incorporated (in toto) herein byreference.

The results of these flammability tests are shown in Table ll.

Table II FLAMMABILITY DATA FOR ABS PLASTIC COMPOSITIONS CONTAININGBIS-PI-IENOXY COMPOUNDS FORMULA- BlS-PHENOXY COM- ENHANCING OXYGEN UL 94TION POUND AGENT INDEX No. No. sb,o,,

1. 0 18.5 SB 2. l 15 0 22.0 SB 3. I I 5 29.0 SE-O 4. 2 15 0 22.5 $13 5.2 15 5 211.5 SE1 6. 5 15 0 23.0 $1; 7. 5 15 5 30.5 SE0 8. 7 15 0 23.5513 9. 7 15 5 31.5 SE-O 10. s 15 0 22.0 $13 1 1. 8 15 5 28.0 SE-l 12. 100 22.5 $1; 13. 10 15 5 28.0 SE-l 14. 12 15 0 23.5 SB 15. 12 15 5 31.0SE-O I6. 14 15 0 230 SB 17. 14 15 5 30.5 85-0 1s. 16 15 0 22.5 $1; 19.16 15 5 31.0 SEC 20. 1s 15 0 24.0 s13 21. 1s 15 5 32.5 815-0 22. 21 15 022.0 $1; 23. 21 15 5 29.5 SE-O 24. 22 15 0 24.5 513 25. 22 15 5 33.0SE-O 26. 23 15 5 32.5 sE-o Referring to Table II, the bis-phenoxycompound number relates to the structural formulae heretofor set forthin Table I; a difference of 2 percent of the Oxygen Index values isconsidered significant; and the UL 94 values are on a graduated scalewherein the highest degree to lowest degree of flame retardancy isrespectively SE-O, SE-l, SE-2, SB and Burns.

The results shown in Table II demonstrate the unique effectiveness ofthese bis-phenoxy compounds as flame retardants for ABS. Specifically,formulation No. 1 (the control) had a 0.]. of 18.5 and UL 94 value ofSB. In Nos. 2, 4, 6, 8,10, l2, l4, l6, 18, 2O, 22 and 24, the use of theparticular bis-phenoxy compound results in a significant increase(3.5-6.0 percent) in fire retardancy as measured by 0.1. (While theseformulations also had a SB rating, UL 94, the individual U.L. rating hasa wide range of values and thus the 0.1. number is, in this case, moreindicative of increased flame retardancy).

The use of an enhancing agent such as Sb O to promote a cooperativeeffect between such agent and the bis-phenoxy compound is fullydemonstrated via the results obtained from testing formulation Nos. 3,5, 7, 9,ll,l3,l5,17, 19, 21, 23, 25 and 26. The highest UL 94 ratingsand significantly higher 0.]. values (9.5l4.5 percent increase) areobtained.

EXAMPLE II Example I is repeated twice; once using a 10 percentbis-phenoxy compound level and 3% Sb O level and EXAMPLE III Portions ofthe solid samples of Formulation Nos. l-26 prepared according to theabove described procedure of Example I are subjected to the followingASTM tests in order to ascertain other properties of the resultantplastic composition:

Tensile Strenght (at break) Flexural Strength Flexural Modulus NotchedIzod Impact Heat Distortion Temperature (HDT) ASTM Test No. D638-6IT;

: ASTM Test No. D790-63;

: ASTM Test No. D790-63;

: ASTM Test No. D256-56; and

: ASTM Test N0. D648-56.

Each of the aforementioned ASTM Tests are standard tests in the art andare utilized collectively in order to ascertain the efficacy of apolymeric system as an overall flame retarded composition for commercialapplication. All of these ASTM Tests are to be consid- EXAMPLE IV Theprocedure of Examples I and III are repeated except that the enhancingagent used is zinc borate instead of Sb O Substantially the same resultsare obtained using zinc borate as those obtained using Sb O EXAMPLE VStrip samples of each of Formulation Nos. 1 through 26 Table II, aresubjected to light stability tests via the use of a Weather-Ometer,model 25/l 8 W. R., Atlas Electrical Devices Company, Chicago, Ill.Utilizing an operating temperature of F and a 50 percent relativehumidity, each strip is subjected to 200 hours of 9 10 simulateddaylight via the use of a carbon arc. The What is claimed is: resultsshow that after 200 hours, there is no significant 1. A plasticcomposition containing acrylonitrilediscoloration in any strip testedand which demonbutadiene styrene polymer having incorporated thereinstrates that the present invention compositions are an effective amountof a flame retardant which is a bishighly resistant to deterioration bylight. 5 phenoxy compound having the formula:

A A r 2 O (alkylene) O Z r EXAMPLE V] wherein Z is bromine; m and m areintegers having a value of l-4; i and i are integers having a value of lor 5 2; alkylene is a straight or branched chain alkylene group havingfrom 1 to 6 carbon atoms; and A is selected from the group consisting ofcyano, nitro, lower alkoxy, lower alkyl, fluorine, dialkylamino, phenyl,halo-phenyl, benzyl, or halobenzyl, with the proviso that when m or m'is 4, ior i respectively is 1.

Samples of each of Formulation Nos. 1 through 26 Table II, are subjectedto temperature (thermal) stability tests via the use of thermalgravimetric analysis (TGA). This test employed the use of ThermalBalance, model TGS-l, Perkin-Elmer Corporation, Norwalk, Conn. and anelectrical balance, Cahn 2580 model, Cahn Instrument Company, Paramount,Calif. The results of these tests show that the bis-phenoxy and are both1' compounds Containing Formulations had more than 3. The composition asset forth in claim 1 wherein i adequate stability for melt processingand subsequent and are both 2 heat aging high temperature applications)and thus 4. The composition as set forth in claim 2 wherein Ademonstrating that the particular bis-phenoxy comis cyano pound? arequlte compatible plastic material 5. The composition as set forth inclaim 2 wherein A The b1s phenoxy compound stability thus aids in proisniml viding sufficient flame retardancy at the plastic decom- Thecomposition as Set forth in claim 2 wherein A position temperature. Thistest also demonstrates that i lower aikoxyi these e p do o exhrbrrrnrgratron- 7. The composition as set forth in claim 2 wherein A In viewof the foregoing Examples and remarks, it is is lower silky]v Seen thatthe Plastic eomposrrions, which incorporate 8. The composition as setforth in claim 2 wherein A these compounds, possess characteristicswhich have i fl i been Unobraineble in the Prior Thus, the use of 9. Thecomposition as set forth in claim 2 wherein A these compounds in theabove described plastic matei di ]k i i rial as flame retardantstherefor is quite unique since it 10 The composition as set f h i l i 2wh r in is not possible to predict the effectiveness and function- A i hl, y of y Particular material in y P y System 11. The composition as setforth in claim 2 wherein until it is actively undergone incorporationtherein and 40 A i halo-phenyl, the resultant Plastic composition testedaccording to 12. The composition as set forth in claim 2 wherein variousASTM Standards. Furthermore, it is necessary, A i b h in order to havecommercial utility, that the resultant 13 T composition as t f th iclaim 2 wherein flame retarded plastic composition possess characteris-A is i tics such as being non-toxic. Use of these compounds 14 Thcomposition as t f th in claim 1 wherein in the plastic material hasaccomplished all of these oblk l i CH l 15. The composition as set forthin claim 1 wherein The above examples have been described in theforealkylene is lgoing Specification for the Purpose of illustration and16. The composition as set forth in claim 1 wherein not limitation. Manyother modifications and ramificaalkylene i C l-{ tions will naturallysuggest themselves to those skilled 7 The composition as set f rth i l i1 h ein in the art based on this disclosure. These are intended aikyieneis (I i-[ to be comprehended as within the scope of this invention.

2. The composition as set forth in claim 1 wherein i

1. A PLASTIC COMPSOTION CONTAINING ACRYLONITRILE-BUTADIENE STYRENEPOLYMER HAVING INCORPORATED THEREIN AN EFFECTIVE AMOUNT OF A FLAMERETARDANT WHICH IS A BIS-PHENOXY COMPOUND HAVING THE FORMULA:
 2. Thecomposition as set forth in claim 1 wherein i and i'' are both
 1. 3. Thecomposition as set forth in claim 1 wherein i and i'' are both
 2. 4. Thecomposition as set forth in claim 2 wherein A is cyano.
 5. Thecomposition as set forth in claim 2 wherein A is nitro.
 6. Thecomposition as set forth in claim 2 wherein A is lower alkoxy.
 7. Thecomposition as set forth in claim 2 wherein A is lower alkyl.
 8. Thecomposition as set forth in claim 2 wherein A is fluorine.
 9. Thecomposition as set forth in claim 2 wherein A is dialkylamino.
 10. Thecomposition as set forth in claim 2 wherein A is phenyl.
 11. Thecomposition as set forth in claim 2 wherein A is halo-phenyl.
 12. Thecomposition as set forth in claim 2 wherein A is benzyl.
 13. Thecomposition as set forth in claim 2 wherein A is halo-benzyl.
 14. Thecomposition as set forth in claim 1 wherein alkylene is CH2.
 15. Thecomposition as set forth in claim 1 wherein alkylene is C2H4.
 16. Thecomposition as set forth in claim 1 wherein alkylene is C3H6.
 17. Thecomposition as set forth in claim 1 wherein alkylene is C4H8.